Bekhorot 24: Nursing without Bearing Offspring?

<p>One who purchases a nursing female animal from a non-Jew - and the question is whether that animal can conclusively be said to have born progeny before, or perhaps the animal was nursing another animal&#39;s offspring, without having borne any herself. Also, what if the first-born has a blemish? What about the slaughtering of the first-born? How one finds the best place for the slaughtering - moving/parting/plucking hair without shearing it. Maybe plucking IS the same as shearing... but it&#39;s allowed because the goal is dramatically different (moving the hair or fur aside vs. shearing it).</p>